Fluidic devices having incorporated electrodes

ABSTRACT

The invention provides fluidic devices having incorporated electrodes. One device comprises a card and first and second caddy segments. The first caddy segment comprises first and second electrodes. The second caddy segment comprises first and second reservoirs disposed on a first surface of the second segment, a channel disposed on a second surface of the second segment, and first and second vias extending between the first and second surfaces. The first caddy segment is attached to the first surface of the second caddy segment. The card is attached to the second surface of the second caddy segment such that the card provides a closed surface for the device.

This application is a continuation-in-part of, and claims the benefitof, U.S. patent application Ser. No. 13/030,379 filed Feb. 18, 2011 nowSer. No. 8,367,021, which is a continuation-in-part of, and claims thebenefit of, U.S. patent application Ser. No. 12/843,557 filed Jul. 26,2010, and issued on Dec. 19, 2012, as U.S. Pat. No. 8,202,486, whichclaims the benefit of and priority to U.S. Provisional Application No.61/233,392 filed Aug. 12, 2009, and U.S. Provisional Application No.61/266,030 filed Dec. 2, 2009, the disclosures of which are hereinincorporated by reference. This application also claims the benefit ofand priority to U.S. Provisional Application No. 61/307,198 filed Feb.23, 2010, and U.S. Provisional Application No. 61/409,772 filed Nov. 3,2010, the disclosures of which are herein incorporated by reference.

TECHNICAL FIELD

The present disclosure is in the field of devices, systems, and methodsfor processing, separating, isolating, and/or analyzing samplecomponents. In particular, described herein are fluidic devices havingincorporated electrodes, systems for using such devices, and methods formanufacturing such devices. The invention also provides fluidic devicesconfigured to absorb joule heating within the device.

BACKGROUND OF THE INVENTION

Separations-based analyses are a prominent part of biological research,allowing one to characterize different biological samples, reactionproducts and the like. Examples of some of the more prevalentseparations-based analyses include electrophoretic separations ofmacromolecular species, e.g., proteins and nucleic acids.Electrophoresis, e.g., capillary electrophoresis, has been establishedas a highly effective method for separating macromolecular species inorder that they might be further characterized. Protein and nucleic acidmolecules are two major examples of molecular species that are routinelyfractionated and characterized using electrophoretic systems.

Both microfluidic and macrofluidic devices have been applied inseparations-based analyses. Examples of novel microfluidic devices andmethods for use in the separation of molecular and macromolecularspecies by electrophoretic means are described in U.S. Pat. Nos.5,958,694, 6,032,710, and 7,419,784, for example, the entire contents ofwhich are incorporated by reference herein. In such devices, the samplecontaining the molecular or macromolecular species for which separationis desired is placed in one end of a separation channel located in afluidic substrate, and a voltage gradient is applied along the length ofthe channel. As the sample components are electrophoreticallytransported along the length of the channel and, optionally, through aseparation (sieving) matrix disposed therein, those components areresolved. The separated components are then detected at a detectionpoint along the length of the channel, typically near the terminus ofthe separation channel downstream from the point at which the sample wasintroduced. Following detection, the separated components may bedirected to a collection reservoir/well in the device (or to an externaldevice such as a multiwell plate using a capillary pipettor, forexample) for subsequent extraction or disposal.

In many situations, it is desirable to extract selected fragments ofinterest, such as DNA (deoxyribonucleic acid) fragments, following theseparation of the fragments into bands in the separation matrix forfurther processing or analysis, e.g., restriction enzyme modification,T4 ligation, PCR (polymerase chain reaction) amplification, massspectroscopy, or polynucleotide kinase reactions. The typical processused by laboratory researchers for extracting and isolating selected DNAfragments of interest (and other desired nucleic acid and proteinfragments) from a separation matrix (such as an agarose gel) involvesstaining the separated fragments and then shining UV (ultraviolet) lighton the fragments to visualize the separated bands. A razor blade is thenused to manually cut the gel above and below each fragment of interest.The DNA must then be extracted and purified from the gel slice. Therecovered DNA can then be used for further processing or analysis. Thisextraction process, however, is time consuming, laborious, andpotentially damaging to the DNA (e.g., nicking of the DNA can occur ifthe DNA is exposed to UV light too long while the fragments of interestare being illuminated for excision).

Thus, in performing separations-based analyses, it would be desirable tobe able to also isolate or extract one or more of the separatedcomponents in the device itself for further analysis or processing. Therecovered or isolated fragments could then be used for a variety ofdifferent processes including, for example, the following: amplificationusing polymerase chain reaction (PCR); ligation reactions for cloningsmall to medium-sized strands of DNA into bacterial plasmids,bacteriophages, and small animal viruses to allow the production of pureDNA in sufficient quantities to allow its chemical analysis; reactionsto dissolve a separated protein or nucleic acid component in a suitablematrix for further analysis by a mass spectrometer using, for example,Matrix-Assisted Laser Desorption Ionization (MALDI); binding reactionsto bind a labeling agent to one or more separated protein or nucleicacid components for further analysis; or other similar post-detectionprocesses. In addition, in the case of PCR samples, it is important tobe able to separate smaller dimer and primer molecules from the mainnucleic acid fragments in the sample and then isolate and collect themain nucleic acid fragments for further analysis or processing, whiledirecting the smaller primer and dimer components to a wastereservoir/well for removal and subsequent disposal.

Typically, the electrodes used in performing electrophoretic separationsin a fluidic device are included in an instrument that receives thefluidic device, rather than in the fluidic device itself. Because theinstrument electrodes are not disposable and are used serially withmultiple devices, contamination of the samples, reaction mixtures, andreaction products may result. In some separations-based applications,limited contamination is not a problem; however, when a component ofinterest is to be isolated or extracted from a sample, avoidingcontamination of a subsequent sample with components of an earliersample can be crucial. Therefore, it would be advantageous to provideimproved fluidic devices that incorporate electrodes into the devices,eliminating the need for multi-use electrodes being included in theinstrument that receives the devices.

SUMMARY OF THE INVENTION

One aspect of the present invention is a fluidic device havingincorporated electrodes. A first device comprises a card and a caddy.The card comprises a channel having first and second ends, the channeldisposed within the card. The card further comprises first and secondvias in fluid communication with the channel through an upper surface ofthe card and first and second electrodes disposed on the upper surfaceof the card. The vias in the top portion of the card are oriented suchthat they are in communication with at least one of the channels and/orchambers formed in the interior portion of the device. The first via andfirst electrode are positioned adjacent to the first end of the channel,and the second via and second electrode are positioned adjacent to thesecond end of the channel. The caddy comprises first and secondreservoirs. The caddy is attached to the card such that the firstreservoir is positioned over the first via and a portion of the firstelectrode, the second reservoir is positioned over the second via and aportion of the second electrode, and a portion of each of the firstelectrode and the second electrode is accessible for dry electricalcontact.

Another fluidic device having incorporated electrodes comprises a cardand a caddy. The card comprises a channel having first and second ends,the channel disposed within the card. The card further comprises a firstvia in fluid communication with the channel through an upper surface ofthe card, the first via positioned adjacent to the first end of thechannel, and a second via in fluid communication with the channelthrough the upper surface of the card, the second via positionedadjacent to the second end of the channel. The caddy comprises first andsecond reservoirs and first and second electrodes. The first electrodeis positioned such that a first portion of the first electrode extendsinto the first reservoir and a second portion of the first electrode isaccessible for dry electrical contact, and the second electrode ispositioned such that a first portion of the second electrode extendsinto the second reservoir and a second portion of the second electrodeis accessible for dry electrical contact. The caddy is attached to thecard such that the first reservoir is positioned over the first via andthe second reservoir is positioned over the second via. The electrodesmay be disposed on deformable tabs or they may be fabricated asstructures independent of the caddy and inserted into openings in thecaddy.

Another aspect of the present invention is a fluidic device configuredto absorb joule heating within the device, the device comprising a cardand a caddy. The card comprises a channel having first and second ends,the channel disposed within the card. The card further comprises firstand second vias in fluid communication with the channel through an uppersurface of the card. The first via is positioned adjacent to the firstend of the channel, and the second via is positioned adjacent to thesecond end of the channel. The caddy comprises first and secondreservoirs. The caddy is attached to the card such that the firstreservoir is positioned over the first via and the second reservoir ispositioned over the second via. The first reservoir extends over an areacovering substantially a first longitudinal half of the channel, and thesecond reservoir extends over an area covering substantially a secondlongitudinal half of the channel.

Yet another aspect of the present invention is a system for isolatingone or more sample components of a sample material following separationof the sample material into a plurality of sample components. The systemcomprises a device having incorporated electrodes such as has beendescribed herein, a detector in sensory communication with the device, afluid direction system, and a processor operably coupled to the detectorand the fluid direction system.

Still another aspect of the present invention is a method ofmanufacturing a fluidic device having incorporated electrodes. A firstmethod comprises providing a card, providing a caddy, and attaching thecaddy to the card. The card comprises a channel, first and second vias,and first and second electrodes. The channel is disposed within the cardand has first and second ends. The first and second vias are in fluidcommunication with the channel through an upper surface of the card. Thefirst and second electrodes are disposed on the upper surface of thecard. The first via and first electrode are positioned adjacent to thefirst end of the channel, and the second via and second electrode arepositioned adjacent to the second end of the channel. The caddy comprisefirst and second reservoirs. The caddy is attached to the card such thatthe first reservoir is positioned over the first via and a portion ofthe first electrode, the second reservoir is positioned over the secondvia and a portion of the second electrode, and a portion of each of thefirst electrode and the second electrode is accessible for dryelectrical contact.

A second method comprises providing a card, providing a caddy, andattaching the caddy to the card. The card comprises a channel and firstand second vias. The channel is disposed within the card and has firstand second ends. The first via is in fluid communication with thechannel through an upper surface of the card and is positioned adjacentto the first end of the channel. The second via is in fluidcommunication with the channel through the upper surface of the card andis positioned adjacent to the second end of the channel. The caddycomprises first and second reservoirs and first and second electrodes.The first electrode is positioned such that a first portion of the firstelectrode extends into the first reservoir and a second portion of thefirst electrode is accessible for dry electrical contact, and the secondelectrode is positioned such that a first portion of the secondelectrode extends into the second reservoir and a second portion of thesecond electrode is accessible for dry electrical contact. The caddy isattached to the card such that the first reservoir is positioned overthe first via and the second reservoir is positioned over the secondvia.

The aforementioned and other features and advantages of the inventionwill become further apparent from the following detailed description ofthe presently preferred embodiments, read in conjunction with theaccompanying drawings, which are not to scale. In the drawings, likereference numbers indicate identical or functionally similar elements.The detailed description and drawings are merely illustrative of theinvention, rather than limiting, the scope of the invention beingdefined by the appended claims and equivalents thereof.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIGS. 1A and 1B are an exploded view and an assembled view,respectively, of a multilayer fluidic card with incorporated electrodes,in accordance with the present invention;

FIGS. 2A and 2B are schematic illustrations of the multilayer fluidiccard of FIG. 1 positioned adjacent to a caddy containing reservoirs, inaccordance with the present invention, FIG. 2A showing the carduppermost and FIG. 2B showing the caddy uppermost;

FIG. 3A is a top view of the multilayer fluidic card and caddyillustrated in FIGS. 2A and 2B assembled into a fluidic device; FIGS. 3Band 3C show cross-sectional views of the fluidic device of FIG. 3A, andFIG. 3D shows an enlarged view of a portion of FIG. 3B;

FIGS. 4A and 4B are an exploded view and an assembled view,respectively, of another fluidic device having incorporated electrodes,in accordance with the present invention;

FIGS. 5A, 5B, and 5C are a top view, a bottom view, and across-sectional view, respectively, of the fluidic device of FIGS. 4Aand 4B, in accordance with the present invention;

FIGS. 6A and 6B are a bottom view and an angled top view, respectively,of a channel sheet, in accordance with the present invention;

FIGS. 7A, 7B, 7C, and 7D are a top view, a bottom view, an angled bottomview, and an angled top view, respectively, of the caddy of FIGS. 4A,4B, and 5A-5C, in accordance with the present invention, the caddyhaving incorporated electrodes;

FIGS. 8A and 8B are an exploded view and a top view, respectively, ofthe patterned/punched label also seen in FIG. 4A, in accordance with thepresent invention;

FIGS. 9A and 9B are an exploded view and an assembled view,respectively, of yet another fluidic device having incorporatedelectrodes, in accordance with the present invention;

FIGS. 10A and 10B are a top view and a bottom view, respectively, of thefluidic device of FIGS. 9A and 9B, while FIGS. 10C and 10D arecross-sectional views of the same fluidic device; and

FIGS. 11A and 11B are exploded views shown from the top and bottom,respectively, of a fluidic device in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

One aspect of the present invention is a fluidic device havingincorporated electrodes. The fluidic device comprises a multilayerfluidic card and a caddy. The electrodes of the fluidic device may beincorporated into either the card or the caddy.

One embodiment of a fluidic device having incorporated electrodes, inaccordance with the present invention, is illustrated in FIGS. 1A-3D.The device comprises a multilayer fluidic card 100 and a caddy 200. Inthe present embodiment, the electrodes are incorporated into themultilayer card. Card 100 comprises a top sheet 110, a channel sheet120, and a bottom sheet 130. Top sheet 110 includes wells 101 and 102,electrodes 112, and vias 114. Channel sheet 120 includes channels 122.Caddy 200 includes wells 201 and 202 and reservoirs 205.

FIG. 1A shows an exploded view of multilayer card 100, while FIG. 1Bshows the card assembled. As seen in FIG. 1A, top sheet 110 includes aplurality of electrically isolated electrodes 112 disposed on a topsurface of the top sheet and, therefore, disposed on a top surface ofthe multilayer card. While eight electrodes are shown in FIGS. 1A and 1Bpositioned on two edges of a substantially rectangular sheet, the numberand positioning of the electrodes may vary as may the shape of the card.In the present embodiment, electrodes 112 are fabricated using a carbonconductive paste. In alternative embodiments, the electrodes maycomprise different or additional materials, including, for example,gold, copper, platinum, silver/silver chloride paste, and otherconductive materials. The electrodes may be patterned onto top sheet 110by screen printing, pad printing, ink-jet printing, stenciling, or othersimilar methods. Alternatively, the electrodes may be formed separatelyand attached to the sheet using methods known in the art.

The electrodes may be fabricated using a single material or multiplematerials. For example, multiple materials may be used where one of theelectrode materials has high conductivity but is incompatible withliquids to be used in and with the device. In this case, electrodes maybe fabricated by applying a chemically compatible material (e.g., acarbon conductive paste) to regions of the device that will come intocontact with a liquid, applying a second material (e.g., ahigh-conductivity material such as silver) outside of the regions of thedevice that contact a liquid, and connecting the second material to thechemically compatible material. Alternatively, a chemically incompatibleconductive material may be applied first to top sheet 110 and thencovered completely with a chemically compatible conductive material. Inthis way, low electrical resistance is achieved, but a liquid within thedevice is exposed only to a chemically compatible conductive material.

Each via 114 extends through top sheet 110 to provide fluidcommunication with at least one channel 122 formed in channel sheet 120.Thus, the configuration of vias 114 in top sheet 110 is based on theconfiguration of the channel or channels 122 in channel sheet 120. Whileone configuration of vias and channels is illustrated in the figures,other configurations are possible. Vias 114 and channels 122 may beformed using techniques known in the art such as molding, etching,drilling, laser cutting, and punching.

Bottom sheet 130 provides a closed bottom surface for channels 122 inchannel sheet 120, resulting in the channels being disposed within thecard. Alternatively, channel sheet 120 and top sheet 110 may be combinedin a single shaped layer that includes channels 122 etched, molded, orotherwise formed into the single layer, as seen, for example, in FIGS.6A and 6B and described below. In this alternative, the shaped layerwill also include electrodes, vias, and wells. In yet anotheralternative, channel sheet 120 and bottom sheet 130 may be combined in asingle shaped layer that includes channels 122 etched, molded, orotherwise formed into the single layer. When viewed from the top, such astructure would appear similar to structure 100 as it is shown in FIG.2A. In still another alternative, shown in FIG. 11B, the card structuresmay be formed into the caddy, so that the card consists of only a bottomsheet.

FIG. 1B shows multilayer card 100 assembled, with top sheet 110 alignedwith channel sheet 120, which is aligned with bottom sheet 130. Thethree sheets are bonded together using methods known in the art.Channels 122 are shown in FIG. 1B as if seen through a translucent ortransparent top sheet 110. However, if optical detection is required,top sheet 110 may be opaque to prevent unwanted excitation andfluorescence of the liquid contained in the channels, and bottom sheet130 may be transparent to permit detection. Various detection schemesmay be employed with devices according to the present invention, and sothe layers may be formed from whatever material is appropriate to eitherprevent excitation or permit detection. The same material or differentmaterials may be employed in the various layers, with poly(methylmethacrylate) (PMMA) and cyclic olefin copolymer (COC) being just twopossible materials.

FIGS. 2A and 2B show exploded views of multilayer card 100 and a caddy200, with the card uppermost in FIG. 2A and the caddy uppermost in FIG.2B. In operation, the caddy would be uppermost as shown in FIG. 2A. Theconfiguration of reservoirs 205 in caddy 200 is determined by theconfiguration of vias 114 in top sheet 110, which, as described above,is based on the configuration of the channel or channels 122 in channelsheet 120. Thus, while one configuration of reservoirs, vias, andchannels is illustrated in the figures, embodiments of the device admitvariation in the number and configuration of the various structures tohelp improve operational efficiency. When used to carry out anelectrophoretic separation, a card includes a minimum of one channel,two vias, and two electrodes, while the caddy includes a minimum of tworeservoirs.

Caddy 200 is bonded to card 100 as seen in FIG. 3A, resulting in adevice having electrically isolated electrodes feeding into separatedchannels. Because card 100 is slightly larger than caddy 200, a portionof each electrode extends beyond the caddy and is accessible at the edgeof the card as seen in FIG. 3A. As is evident from FIGS. 2A and 2B, whencaddy 200 is mated with card 100, each reservoir 205 overlaps both aportion of an electrode 112 and a via 114. When a liquid is introducedinto the reservoir, the liquid provides a conductive path between theelectrode and a channel in fluid communication with the via. Thus, dryelectrical contact can be made at the edge of the device that transferscurrent through the electrodes into the liquid-containing reservoirs.Therefore, an electrical contact that is included in an instrumentdesigned to operate the device can be configured to contact only theportion of an electrode that extends beyond caddy 200 and not any liquidcontained within the device, thereby avoiding cross-contaminationbetween devices that are inserted into the instrument. As is evidentfrom FIGS. 1A and 1B, wells 101 and 102 in the card are in fluidcommunication with channels 122. Wells 201 and 202 in caddy 200 arealigned with wells 101 and 102 in the card as seen in FIG. 2B, therebypermitting one or more samples to be introduced into the device throughwells 201 and 101 and one or more isolated sample components to beremoved from the device through wells 202 and 102.

While it is presently preferred that the card be slightly larger thanthe caddy as described above, allowing a portion of each electrode toextend beyond the caddy, in alternative embodiments, the caddy and thecard could be the same size or the caddy could even be larger than thecard. In these alternatives, the portions of the electrodes disposedoutside the reservoirs could be accessible through openings formed inthe caddy or indentations in the edges of the caddy.

FIGS. 3B and 3D show additional structures 215 that can be included inthe reservoirs 205 of caddy 200. These structures can prevent aseparation matrix contained within a channel from flowing onto anelectrode while allowing electrical contact by means of a buffer thattouches both the separation matrix and the electrode.

Another embodiment of a fluidic device having incorporated electrodes,in accordance with the present invention, is illustrated in FIGS. 4A-8B.The illustrated device comprises a multilayer fluidic card 400 and acaddy 500. In this embodiment, the electrodes are incorporated into thecaddy rather than into the fluidic card. The multilayer card comprises achannel sheet 420 and a bottom sheet 430. Channel sheet 420 includeswells 401 and 402, vias 414, and channels 422. Electrodes 512 aredisposed on deformable tabs 516 located on the top surface of caddy 500.Caddy 500 also includes wells 501 and 502 and reservoirs 505.

In the present embodiment, multilayer card 400 includes two layers: ashaped layer and a flat layer. The shaped layer, channel sheet 420, isbest seen in FIGS. 6A and 6B. FIG. 4A shows the top surface of channelsheet 420. The bottom surface of channel sheet 420 would appear similarto the view seen in FIG. 5B. In FIG. 5B, which shows the bottom surfaceof the fluidic device, channels 422 are shown as if seen through atranslucent or transparent bottom sheet 430. Vias 414 pass entirelythrough channel sheet 420 and can be seen in all of FIGS. 4A, 5B, 6A,and 6B. Vias 414 may be formed using any appropriate technique known inthe art, for example molding, etching, drilling, and laser cutting. Inthe present embodiment, channels 422 are machined into the bottomsurface of sheet 420, but they may be formed using other techniques,e.g., molding, etching, stamping, and grinding. As is best seen in FIG.6A, vias 414 provide fluid communication with channels 422. Bottom sheet430 provides a closed bottom surface for channels 422 in channel sheet420.

Alternative embodiments of multilayer card 400 are, of course, possible.For example, the multilayer card may include a top sheet, channel sheet,and bottom sheet, with vias and wells formed in the top sheet andchannels formed in the channel sheet in the appropriate configurations,and the bottom sheet providing a closed bottom surface for the channels.Such a structure would appear similar to the multilayer fluidic cardseen in FIG. 1A but without electrodes disposed on the surface of thecard. In still another alternative, the card structures may be formedinto the caddy, so that the card consists of only a bottom sheet.

Various detection schemes may be employed with devices according to thepresent embodiment, and so the layers of the multilayer fluidic card maybe formed from whatever material is appropriate to either preventexcitation or permit detection. The same material or different materialsmay be employed in the various layers, with PMMA and COC being just twopossible materials.

Caddy 500 includes both electrodes 512 and reservoirs 505. Electrodes512 are disposed on deformable tabs 516 to form electrode/tab structureson the top surface of caddy 500. In the present embodiment, electrodes512 are fabricated using a carbon conductive paste. In alternativeembodiments, the electrodes may comprise different or additionalmaterials, including, for example, gold, copper, platinum, silver/silverchloride paste, and other conductive materials. The electrodes may bepatterned onto deformable tabs 516 by screen printing, pad printing,ink-jet printing, stenciling, or other similar methods. In addition, theelectrodes may be formed on the tabs using a co-injection molding or anover-molding process. In alternative embodiments, electrodes 512 may bemetal (or another conductive material) pieces bonded to caddy 500 orinsert molded into the caddy. In these embodiments, electrodes 512 anddeformable tabs 516 are integral structures rather than the electrodesbeing formed separately onto the deformable tabs.

The electrodes may comprise a single material or may comprise multiplematerials. As in the previously described embodiment, multiple materialsmay be used where an electrode material has high conductivity but isincompatible with liquids to be used in and with the device. In thiscase, electrodes may be fabricated by applying a chemically compatiblematerial (e.g., a carbon conductive paste) to regions of deformable tabs516 that will come into contact with a liquid, applying a secondmaterial (e.g., a high-conductivity material such as silver) outside ofthe regions of the tabs that contact a liquid, and connecting the secondmaterial to the chemically compatible material. Alternatively, achemically incompatible conductive material may be applied first todeformable tabs 516 and then covered completely with a chemicallycompatible conductive material. As a result, low electrical resistanceis achieved, but any liquid within the device is exposed only to achemically compatible material.

The deformable tabs are fabricated in a first position in the plane ofthe upper surface of the caddy. The tabs are deformed out of plane intoa second position during a later stage of manufacture of the device.Thus, the term “deformable tab” is defined herein as a tab that isfabricated in a first (not deformed) position and that assumes a second(deformed) position during a later stage of manufacture of the device.In the second position, at least a portion of each tab 516 extendsdownward into one of reservoirs 505. FIGS. 7A and 7D, for example, showsdeformable tabs 516 in the first position, while FIG. 5C shows the tabsin the second position. Electrodes 512 may be formed on (or bonded to ormolded into) the deformable tabs either before or after the tabs aredeformed into the second position.

It may be advantageous to minimize the stress in the tab/electrodestructure because the resistance of the electrode may increase whenstretched or the electrode and/or tab may fracture when deformed. In oneembodiment, it may be preferred to deform the tab/electrode structure inthe shape of an arc, rather than at an angle as shown in FIG. 5C, wherethe deformation of the tab/electrode structure is localized at a hingepoint. Alternatively, or in addition, the tab/electrode structure couldhave multiple deformation points instead of a single one as shown inFIG. 5C. The deformation point(s) may also be thinned to reduce stress.One means for thinning can be seen as semi-circular cutouts at 517 inFIG. 5C.

Caddy 500 is bonded to card 400 as seen in FIG. 4B and FIGS. 5A-5C.Either before or after the caddy and card are bonded together, eachelectrode/tab structure is deformed out of plane, as shown in FIG. 5C.The electrode/tab structures are sized such that when reservoirs 505contain a liquid, the electrodes reach down into the liquid. In thisway, dry electrical contact can be made on the top of caddy 500 totransfer current into the liquid. Features (not shown) could be includedon the top of the card or as part of the caddy that lock the electrodetabs in place after deforming.

While the figures show the contact areas for the dry electrodes spreadout across the top of the device, the conductive traces could be routedto a single, more confined region of the device. This type ofarrangement is often preferred for supporting a common electricalinterface.

The configuration of reservoirs 505 in caddy 500 is partially determinedby the configuration of vias 414 in channel sheet 420, as when a liquidis introduced into a reservoir, the liquid provides a conductive pathbetween the electrode 512 that reaches down into the liquid and achannel 422 through a via 414. Liquid disposed in a first reservoirprovides a conductive path between a first electrode and a first end ofa channel through a first via; liquid in a second reservoir provides aconductive path between a second electrode and a second end of thechannel through a second via. One configuration of reservoirs, vias, andchannels is illustrated in the figures; however, embodiments of thedevice admit variation in the configuration of the various structures tohelp improve operational efficiency.

One particular advantage to the reservoir configuration of the presentembodiment, which is best seen in FIG. 5C and FIG. 7C, is that whencaddy 500 is joined to card 400, reservoirs 505 are directly abovechannels 422, in which electrophoresis may be carried out. In thisconfiguration, liquid in the reservoirs positioned directly over thechannels acts as a heat sink that can absorb joule heating during theelectrophoresis process. In addition, this configuration is very compactand allows for a minimal total volume for the device. Reservoirs 505 aresized such that in combination they extend over an area coveringsubstantially all of each of the channels of the device. This can beseen, for example, in FIG. 5C. It will be appreciated that all ofreservoirs 505 may be of equal size or may, alternatively, be of unequalsize.

A patterned/punched label, seen at 600 in FIGS. 4A, 8A, and 8B, may beadded on top of the caddy so that liquid within the device is completelysealed from the outside environment but openings are provided in thelabel to allow contact to the dry electrodes. As seen in FIG. 8A, label600 may comprise two layers, a cover sheet 610 and a patterned/punchedsheet 620. Cover sheet 610 is removed by the user of the device, leavingpatterned/punched sheet 620 in place over caddy 500.

Where a label is included in the device, the electrodes may be printedonto (or otherwise disposed on) the label rather than on the caddy. Forexample, electrode tabs could be incorporated into a flexible label aspunch outs. In another embodiment, a laminate that includes moldedplastic fingers could be applied on top of the caddy instead of beingmolded as part of the caddy. In either of these embodiments, the caddyitself would not be fabricated with deformable tabs, just openings abovethe reservoirs. Prior to use, the electrode tabs on the label would bepunched and pushed into the reservoirs, or the molded plastic fingerswould be bent so as to make electrical contact with a liquid in thecaddy reservoirs. These alternative embodiments would not appearsubstantially different from the embodiment illustrated in the figures.

The device could also include blister packs for reagent storage. Thiswould be desirable if some reagents are not stable when stored mixed inthe device or otherwise need to be kept separate until point of use. Theblister pack could be burst by the user or the instrument, releasing thestored reagent(s) into the reservoirs at the appropriate time.

Plugs (or combs) 701 and 702 can be seen in the figures. These areincluded to help ensure that wells 501 and 502 in caddy 500 and wells401 and 402 in card 400 remain free of any separation matrix containedwithin the device during manufacturing, shipping, and storage. The plugsare removed prior to using the device, permitting one or more samples tobe introduced into the device and one or more isolated sample componentsto be removed from the device through wells 501 and 502, respectively,in the caddy, wells 501 and 502 being aligned with wells 401 and 402 inthe card. The plugs also aid in removing any separation matrix that mayhave adhered to the walls of the wells. The unwanted separation matrixis dislodged from the well walls when the plugs are removed from thewells and drawn out along with the plugs. Preferably the plugs aremanufactured from a porous material, for example a material thermally orlaser sintered from a powder. Plug materials may include, but are notlimited to, polyamide, polypropylene, high density polyethylene (HDPE),ethylene-vinyl acetate (EVA), and polystyrene (PS).

Yet another embodiment of a fluidic device having incorporatedelectrodes, in accordance with the present invention, is illustrated inFIGS. 9A-10D. The illustrated device comprises a multilayer fluidic cardand a caddy 900. In this embodiment, as in the previous embodiment, theelectrodes are incorporated into the caddy rather than into the fluidiccard. As illustrated in FIG. 9A, the multilayer card is card 400, whichis also illustrated in FIG. 4A and has been described above. Alternativemultilayer cards have also been described above and may be used in placeof the illustrated card 400. A separation matrix 924 is disposed withinat least a portion of one or more of the channels included in themultilayer card. Caddy 900 includes wells 901 and 902, reservoirs 905,and electrodes 912. The device further includes a seal 915, vents 918,and a barcode label 925.

In the present embodiment, electrodes 912 are independent structures(i.e., structures that are fabricated separately from the caddy) thatare incorporated into caddy 900 by being inserted (e.g., by being drivenor press-fit) into the caddy. As seen in FIG. 9A, openings 903 areprovided in the caddy through which electrodes 912 extend. Electrodes912 are shown in place within openings 903 in FIG. 10D. While electrodes912 are illustrated in the figures as straight metal pins, they may takeshapes other than the one illustrated and may be fabricated from and/orcoated with a conductive material other than a metal.

Electrodes 912 may be integrated into caddy 900 either before or afterthe caddy is bonded to card 400. An upper portion of each electroderemains accessible on the upper surface of the device while a lowerportion extends down into the reservoir over which the electrode ispositioned. The electrodes are sized such that when reservoirs 905contain a liquid, the electrodes extend down into the liquid. Thus, dryelectrical contact can be made on the top of caddy 900 to transfercurrent into the liquid contained within reservoirs 905. The liquidprovides a conductive path between an electrode and a channel in fluidcommunication with a via in the fluidic card. Liquid disposed in a firstreservoir provides a conductive path between a first electrode and afirst end of a channel through a first via; liquid in a second reservoirprovides a conductive path between a second electrode and a second endof the channel through a second via.

The configuration of reservoirs 905 in caddy 900 is partially determinedby the configuration of the vias in the fluidic card. While oneconfiguration of reservoirs, vias, and channels is illustrated in thefigures, embodiments of the device admit variation in the configurationof the various structures to help improve operational efficiency.However, as noted above, one particular advantage to the reservoirconfiguration of both the present and the previous embodiment is thatthe reservoirs are directly above the channels. Where the channels areused for electrophoresis, liquid in the reservoirs positioned directlyover the channels acts as a heat sink to absorb joule heating during theelectrophoresis process. Reservoirs 905 are sized such that incombination they extend over an area covering substantially all of eachof the channels of the device. This can be seen, for example, in FIG.10D. It will be appreciated that all of reservoirs 905 may be of equalsize or may, alternatively, be of unequal size.

Seal 915 may be a solid sheet of material, such as a heat-seal polymeror foil, that is used to cover the device during shipping.Alternatively, a patterned/punched label such as is seen at 600 in FIGS.4A, 8A, and 8B may be used. Note that various raised areas are providedon the surface of caddy 900. These are especially important when seal915 comprises a heat seal and are used to concentrate heat and pressurenear regions that must be sealed (e.g., wells) and to protect otherregions from contact with the seal (e.g., the exposed upper surfaces ofthe electrodes). The features have narrow rims to reduce the force thata user must exert to peel off the seal before using the device. Thesefeatures may be eliminated if a seal is not used with the device.

Vents 918 are included to protect a sealed device from damage duringshipping and storage. If a device is subjected to conditions such as,for example, heat or reduced pressure while seal 915 is in place, theportion of seal 915 affixed over the area of a plug 701 or 702 mayexpand, creating a vacuum within the plug area. If the vacuum is nototherwise relieved, it can extend beneath the plug and through one ormore of caddy wells 901 or 902 into the associated well(s) 401 and 402within the fluidic card. As can be best seen in FIGS. 9A and 10D, eachof wells 401 and 402 within the fluidic card is fluidly connected with achannel 422. A vacuum that acts on any of these wells can draw aseparation matrix 924 disposed within the channel 422 out of the channeland into the well, affecting the utility of the device. To eliminate thepossibility of a vacuum being communicated from a plug area to a channelthrough one or more wells, vents 918 are positioned adjacent to thewells as seen, for example, in FIGS. 9A, 10A, and 10C. Referring now toFIG. 10C, it can be seen that vents 918 connect each plug area with areservoir 905 below. By connecting the plug area to the reservoir, whichis only partially filled with a fluid (e.g., a buffer), any vacuumcreated during shipping or storage is transferred to the air space overthe fluid within the reservoir. Because the volume of the reservoir ismuch larger than the extra volume created by the expansion of theportion of the seal affixed over the plug area, the vacuum created bythe seal expansion is damped out (by the ratio of the volumes).Additionally, each vent 918 creates a pressure short circuit between awell and a via as can be seen, for example, between well 401 and via 414in FIG. 10D. Therefore, even if there is some residual pressure changedue to expansion of the seal, there is no pressure difference betweenthe channel and the well, and the separation matrix does not flow out ofthe channel.

In the present embodiment, label 925 includes a 2D barcode. The barcodemay encode, for example, lot- or batch-specific information for thedevice.

Yet another embodiment of a fluidic device having incorporatedelectrodes, in accordance with the present invention, is illustrated inFIGS. 11A and 11B. This embodiment is similar to the embodimentdescribed immediately above and illustrated in FIGS. 9A-10D; however, inthe present embodiment, the card structures (i.e., those structuresfound in a fluidic card in the embodiments described above) are formedinto the caddy, with the card 1130 consisting of only a bottom sheet. Tofacilitate forming the card structures into the caddy, the caddycomprises two segments: a first segment 1100, also referred to herein asa top segment, and a second segment 1110, also referred to herein as abottom segment. Electrodes 1112 are incorporated into caddy segment1100. The device may further comprise any of the features previouslydescribed (e.g., vents such as have been described above and illustratedat 918 in FIG. 9A and/or a barcode label such as has been describedabove and illustrated at 925 in FIG. 9A).

As seen in FIGS. 11A and 11B, the caddy includes wells that extendthrough both of the caddy segments, with first well portions 1101 a and1102 a disposed in caddy top segment 1100, second portions 1110 b and1102 b disposed in caddy bottom segment 1110, and third portions 1110 cand 1102 c also disposed in caddy bottom segment 1110. When caddy topsegment 1100 is attached to caddy bottom segment 1110, well portions1101 a, 1101 b, and 1101 c are in fluid communication, and well portions1102 a, 1102 b, and 1102 c are in fluid communication. When the caddysegments are assembled, the well portions combine to form wells that arein fluid communication with channels 1122.

Caddy bottom segment 1110 includes a shaped top surface, seen in FIG.11A, that includes reservoirs 1105, and a shaped bottom surface, seen inFIG. 11B, that includes well portions, as described above, and channels1122. Vias 1114 extend through caddy bottom segment 1110 from the topsurface to the bottom surface and provide fluid communication betweenreservoirs 1105 and channels 1122. For example, a first via providesfluid communication between a first reservoir and a first end of achannel, and a second via provides fluid communication between a secondreservoir and a second end of the channel. Card 1130 is attached tocaddy bottom segment 1110 to provide a closed bottom surface for thedevice, resulting in the structures seen in FIG. 11B being disposedwithin the device.

Reservoirs 1105 are sized such that in combination they extend over anarea that covers substantially all of each of the channels of thedevice. As is evident from FIGS. 11A and 11B, a combination of a firstand a second reservoir extends over an area covering substantially allof each channel of the device. Where channels 1122 are used forelectrophoresis, liquid in reservoirs 1105 acts as a heat sink to absorbjoule heating during the electrophoresis process. Reservoirs 1105 may beof equal or unequal sizes.

In the present embodiment, electrodes 1112 are independent structures(i.e., structures that are fabricated separately from the caddy) thatare incorporated into caddy top segment 1100 by being inserted (e.g., bybeing driven or press-fit) into the caddy. As seen in FIG. 11A, openings1103 are provided in caddy top segment 1100 through which electrodes1112 extend. In FIGS. 11A and 11B, electrodes 1112 are shown in placewithin openings 1103. While electrodes 1112 are illustrated in thefigures as substantially straight metal pins, they may take shapes otherthan the one illustrated. For example, electrodes 1112 may be disposedon deformable tabs according to any of the variations described above.Electrodes 1112 may be fabricated from and/or coated with a conductivematerial other than a metal.

Electrodes 1112 may be integrated into caddy top segment 1100 eitherbefore or after caddy top segment 1100 is attached to caddy bottomsegment 1110 to form a single caddy structure. The top and bottom caddysegments may be attached one to the other by means of an adhesive, asnap-fit design, or other means known in the art. An upper portion ofeach electrode (a first portion) remains accessible on the upper surfaceof the device for dry electrical contact, while a lower portion (asecond portion) of each electrode extends down into the reservoir 1105over which the electrode is positioned. The electrodes are sized suchthat when the reservoirs contain a liquid, the electrodes extend downinto the liquid. Thus, dry electrical contact can be made on the top ofthe device to transfer current into the liquid contained withinreservoirs 1105. The liquid provides a conductive path between anelectrode 1112 and a channel 1122 that is in fluid communication with areservoir 1105 through a via 1114. Liquid disposed in a first reservoirprovides a conductive path between a first electrode and a first end ofa channel through a first via; liquid in a second reservoir provides aconductive path between a second electrode and a second end of thechannel through a second via. The number of channels in the device mayvary from the number illustrated in FIG. 11B.

It should be noted that a caddy similar to those seen in FIGS. 5C, 7C,10C, 10D, 11A, and 11B (i.e., a caddy having reservoirs that extend overthe area occupied by channels and/or chambers in a fluidic device,thereby acting as a heat sink for the channels and/or chambers) willoffer advantages in any number of fluidic devices, not only fluidicdevices incorporating electrodes, but also fluidic devices that areoperated using electrodes located separate from the device in a systemdesigned to receive the fluidic device.

Thus, another aspect of the present invention is a fluidic deviceconfigured to absorb joule heating within the device, the devicecomprising a card and a caddy. Such a device would be, in effect, adevice such as those that have been described above but without theelectrodes. The card may be any of the cards described above andillustrated in the figures. The card comprises a channel having firstand second ends, the channel disposed within the card. The card furthercomprises first and second vias in fluid communication with the channelthrough an upper surface of the card. The first via is positionedadjacent to the first end of the channel, and the second via ispositioned adjacent to the second end of the channel. The caddycomprises at least first and second reservoirs and may appear similar tothe caddy seen in FIG. 7C. The caddy is attached to the card such thatthe first reservoir is positioned over the first via and the secondreservoir is positioned over the second via. The first and secondreservoirs are sized such that the two reservoirs in combination extendover an area covering substantially all of the channel disposed withinthe card.

Another aspect of the present invention is a system for isolating one ormore sample components of a sample material following separation of thesample material into a plurality of sample components. The systemcomprises a device such as those that have been described above as wellas instrumentation for controlling the device. For example, theinstrumentation may comprise a detector positioned in sensorycommunication with a detection region of the device, a processoroperably coupled to the detector and to a fluid direction system that isconfigured to control movement of one or more sample components based oninformation received from the detector. As used herein, the phrase “insensory communication” refers to positioning of a detector such that itis operably connected to the device, i.e., capable of receiving adetectable signal from the contents of the device. In the case ofoptical signals, this requires only that the detector be positioned toreceive the optical signal. The system may be configured tosimultaneously control multiple channels or multiple fluidic circuits.In such a configuration, the fluid direction system may be configured tocontrol the movement of one or more sample components in one channel orfluidic circuit based on information received by the detector in aparallel channel or circuit. Fluid movement may be controlled by the useof electrokinetics, such as electrophoresis or electroosmosis, whereincharged components within the fluid move, and/or the fluid itself moves,in response to the application of positive and negative voltages.Another example includes the application of positive or negative partialpressure to certain areas of the device, so that fluid moves fromlocations of high pressure to locations of low pressure through thechannel or channels of the device. Partial pressures may be applied by apumping mechanism or the application of a vacuum force to a reservoir.Therefore, the fluid direction system includes the capabilities forproviding and controlling forces to move fluids or fluid componentsthrough the channel or channels of the device.

Another system for isolating one or more sample components of a samplematerial following separation of the sample material into a plurality ofsample components comprises a fluidic device having incorporatedelectrodes, a detector in sensory communication with the device, a fluiddirection system, and a processor operably coupled to the detector andthe fluid direction system. The device comprises a card, a first caddysegment, and a second caddy segment. The first caddy segment comprisesfirst and second electrodes. The second caddy segment comprises firstand second reservoirs, a channel, and first and second vias. Thereservoirs are disposed on a first surface of the second segment. Thechannel is disposed on a second surface of the second segment. The viasextend between the first and second surfaces, the first via providingfluid communication between the first reservoir and a first end of thechannel, and the second via providing fluid communication between thesecond reservoir and a second end of the channel.

Yet another aspect of the present invention is a method formanufacturing a fluidic device having incorporated electrodes. In afirst method, a card and a caddy are provided. The card comprises achannel, first and second vias, and first and second electrodes. Thechannel is disposed within the card and has first and second ends. Thefirst and second vias are in fluid communication with the channelthrough an upper surface of the card. The first and second electrodesare disposed on the upper surface of the card. The first via and firstelectrode are positioned adjacent to the first end of the channel, andthe second via and second electrode are positioned adjacent to thesecond end of the channel.

The caddy includes first and second reservoirs. The caddy is attached tothe card such that the first reservoir is positioned over the first viaand a portion of the first electrode, the second reservoir is positionedover the second via and a portion of the second electrode, and a portionof each of the first electrode and the second electrode is accessiblefor dry electrical contact.

In a second method for manufacturing fluidic devices having incorporatedelectrodes, a card and a caddy are provided. The card comprises achannel and first and second vias. The channel is disposed within thecard and has first and second ends. The first via is in fluidcommunication with the channel through an upper surface of the card andis positioned adjacent to the first end of the channel. The second viais in fluid communication with the channel through the upper surface ofthe card and is positioned adjacent to the second end of the channel.

The caddy comprises first and second reservoirs and first and secondelectrodes. The first electrode is positioned over the first reservoir,and the second electrode is positioned over the second reservoir. In oneembodiment of the caddy, the first electrode is disposed on a firstdeformable tab, and the second electrode is disposed on a seconddeformable tab. The tabs are formed on the caddy in a first position andare then deformed out of plane into a second position. The electrodesmay be formed on the tabs either before or after the tabs are deformed,and the tabs may be deformed either before or after the caddy isattached to the card. In a second embodiment of the caddy, the first andsecond electrodes are independent structures (e.g., metal pins) that areincorporated into the caddy by being inserted (driven or press-fit) intoopenings provided in the caddy. In this embodiment, the electrodes maybe incorporated into the caddy either before or after the caddy isattached to the card.

The caddy is attached to the card such that the first reservoir ispositioned over the first via and the second reservoir is positionedover the second via and such that a portion of each of the firstelectrode and the second electrode is accessible for dry electricalcontact.

While the embodiments of the invention disclosed herein are presentlyconsidered to be preferred, various changes and modifications can bemade without departing from the spirit and scope of the invention. Thescope of the invention is indicated in the appended claims, and allchanges and modifications that come within the meaning and range ofequivalents are intended to be embraced therein.

What is claimed is:
 1. A fluidic device having incorporated electrodes,comprising: a card; and a caddy, the caddy comprising a first caddysegment comprising first and second electrodes; and a second caddysegment comprising first and second reservoirs disposed on a firstsurface of the second segment, a channel disposed on a second surface ofthe second segment, and first and second vias extending between thefirst and second surfaces; wherein the first caddy segment is attachedto the first surface of the second caddy segment, and the card isattached to the second surface of the second caddy segment such that thecard provides a closed surface for the device.
 2. The device of claim 1wherein the first via provides fluid communication between the firstreservoir and a first end of the channel, and the second via providesfluid communication between the second reservoir and a second end of thechannel.
 3. The device of claim 1 wherein the first caddy segment isattached to the first surface of the second caddy segment such that afirst portion of the first electrode is accessible for dry electricalcontact and a second portion of the first electrode extends into thefirst reservoir and such that a first portion of the second electrode isaccessible for dry electrical contact and a second portion of the secondelectrode extends into the second reservoir.
 4. The device of claim 3further comprising a liquid disposed in each of the first and secondreservoirs, wherein the liquid disposed in the first reservoir providesa conductive path between the first electrode and the first end of thechannel through the first via, and wherein the liquid disposed in thesecond reservoir provides a conductive path between the second electrodeand the second end of the channel through the second via.
 5. The deviceof claim 1 wherein the caddy further comprises first and second wells influid communication with the channel.
 6. The device of claim 1 whereinthe first and second reservoirs are sized such that the reservoirs incombination extend over an area covering substantially all of thechannel.
 7. The device of claim 1 wherein the second caddy segmentcomprises a plurality of channels, a plurality of first and secondreservoirs, and a plurality of first and second vias.
 8. The device ofclaim 7 wherein each combination of a first and a second reservoir issized such that the combination extends over an area coveringsubstantially all of at least one of the plurality of channels.
 9. Thedevice of claim 7 wherein each channel has a first end and a second endand wherein a first via provides fluid communication between the firstend of each channel and a first reservoir and a second via providesfluid communication between the second end of each channel and a secondreservoir.
 10. The device of claim 7 wherein for each of the pluralityof channels, a first via provides fluid communication between a firstreservoir and a first end of the channel, and a second via providesfluid communication between a second reservoir and a second end of thechannel.
 11. The device of claim 1 wherein the first caddy segmentfurther comprises openings provided in the first caddy segment, andwherein the first and second electrodes are fabricated as structuresindependent of the first caddy segment and are inserted into theopenings in the first caddy segment.
 12. The device of claim 1 whereinthe first electrode is disposed on a first deformable tab and the secondelectrode is disposed on a second deformable tab.
 13. The device ofclaim 12 wherein the deformable tabs are formed into the first caddysegment.
 14. The device of claim 12 wherein the deformable tabs areattached to a surface of the first caddy segment.
 15. The device ofclaim 12 further comprising a label attached to a surface of the firstcaddy segment.
 16. The device of claim 15 wherein the deformable tabsare formed into the label.
 17. The device of claim 15 wherein thedeformable tabs are attached to the label.
 18. The device of claim 12wherein the deformable tabs are deformed during manufacture such that aportion of the first electrode extends downward into the first reservoirand a portion of the second electrode extends downward into the secondreservoir.
 19. The fluidic device of claim 5, the device furthercomprising: first and second vents disposed in the caddy adjacent to thefirst and second wells, the first vent in fluid communication with thefirst reservoir and the second vent in fluid communication with thesecond reservoir, wherein the vents equilibrate pressure differencesthat result when a seal that is affixed over the first and second wellsexpands, creating a vacuum beneath the seal.
 20. A system for isolatingone or more sample components of a sample material following separationof the sample material into a plurality of sample components, the systemcomprising: a fluidic device having incorporated electrodes, the devicecomprising a card; a first caddy segment comprising first and secondelectrodes; a second caddy segment comprising first and secondreservoirs disposed on a first surface of the second segment, a channeldisposed on a second surface of the second segment, and first and secondvias extending between the first and second surfaces, the first viaproviding fluid communication between the first reservoir and a firstend of the channel, and the second via providing fluid communicationbetween the second reservoir and a second end of the channel; and adetector in sensory communication with the device; a fluid directionsystem; and a processor operably coupled to the detector and the fluiddirection system.